Steps to reproduce:

1. Create a table with the following content:
A,B
a1,1
a2,2

2. Set pivot table (Data - Pivot Table - Create...)

3. Drag and drop field A to "Row Field", B to "Data Field".

4. Try to drag B out of "Data Field" (i.e., to move it back to the avaible fieds box).
--> B does not go out of "Data Field".

5. Click on the "Data" label (shown in Column Field), then drag and drop B.
--> "Data" is moved out, rather than B.
--> For further testing, if you now click "OK" then edit pivot layout again, you will see "Data" label is still there, and B is still there too.

Version: 4.4.0.0.beta1
Build ID: 9af3d21234aa89dac653c0bd76648188cdeb683e
Locale: zh_CN
Win 7 X64

Version: 4.3.5.1
Build ID: 8fd0451cc08e6a5310bed8b7ad1c46b93c1c6889